Mordechai Vanunu, the man who exposed Israel's nuclear secrets in 1986, walked out of prison today after 18 years in prison, 11 of them in solitary confinement.

But Vanunu, now 49, is hardly a free man.

He is on probation till October, which means he will have to report every day to a police station. He is prohibited from leaving Israel, being interviewed on the secret nuclear reactor in Dimona, and coming within half-a-kilometre of any foreign embassy, airport or seaport in Israel. He will be kept under strict survelliance to ensure his compliance.

In a statement Tuesday, the Israeli defence ministry said "Mordechai Vanunu has revealed state secrets about the Dimona nuclear plant. He still possesses state secrets including some which he has not revealed. The revelations of these state secrets could seriously damage the security of the state."

Vanunu, a nuclear technician, was hired to work at the secret reactor in the desert town of Dimona in 1976. Fired in 1985, Vanunu left Israel with some rolls of film he had secretly shot at the reactor, which he sold to the Sunday Times along with details of the plant's operations.

He was eventually lured to Italy by Cheryl Hanin, a Mossad seductress who then drugged him and put him on a yatch bound for Israel. He has stayed at the Shikma prison in the coastal town of Ashkelon since.

While hailed by the international anti-nuclear lobby as a hero, Vanunu is seen as a traitor by most Israelis.

Vanunu's release, set for 11 am local time Wednesday, was delayed over confusion about where he would be staying.

Local media reports said he would be staying for the next three months in a luxury apartment in Jaffa rented by the BBC, apparently in exchange for a future exclusive interview with Vanunu. But hours before his release, Israeli prison authorities said that "He has refused to give us his place of residence (after his release) and until he does so he will not be freed."

Apart from the media, waiting for him outside the prison gates were two of his eleven brothers, (the only ones of his 11 siblings who have not denounced him), his attorney, his adoptive parents, and hundreds of supporters from across the world.

In a letter he wrote to a friend from prison, Vanunu says he doesn't plan to sell State secrets to other countries. "My plan is to find a partner and a place to work and to carry on a normal life".